CAN Registers
805
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Controller Area Network (CAN) Module
11.4.1 CANCTL Register (Offset = 0x0) [reset = 0x1]
CAN Control (CANCTL)
This control register initializes the module and enables test mode and interrupts.
The bus-off recovery sequence (see CAN Specification Rev. 2.0) cannot be shortened by setting or
clearing INIT. If the device goes bus-off, it sets INIT, stopping all bus activities. Once INIT has been
cleared by the CPU, the device then waits for 129 occurrences of bus idle (129 * 11 consecutive high bits)
before resuming normal operations. At the end of the bus-off recovery sequence, the Error Management
Counters are reset.
During the waiting time after INIT is cleared, each time a sequence of 11 high bits has been monitored, a
BITERROR0 code is written to the CANSTS register (the LEC field = 0x5), enabling the CPU to readily
check whether the CAN bus is stuck Low or continuously disturbed, and to monitor the proceeding of the
bus-off recovery sequence.
CANCTL is shown in
and described in
Return to
Figure 11-5. CANCTL Register
31
30
29
28
27
26
25
24
RESERVED
R-0x0
23
22
21
20
19
18
17
16
RESERVED
R-0x0
15
14
13
12
11
10
9
8
RESERVED
R-0x0
7
6
5
4
3
2
1
0
TEST
CCE
DAR
RESERVED
EIE
SIE
IE
INIT
R/W-0x0
R/W-0x0
R/W-0x0
R-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x1
Table 11-8. CANCTL Register Field Descriptions
Bit
Field
Type
Reset
Description
31-8
RESERVED
R
0x0
7
TEST
R/W
0x0
Test Mode Enable.
0x0 = The CAN controller is operating normally.
0x1 = The CAN controller is in test mode.
6
CCE
R/W
0x0
Configuration Change Enable.
0x0 = Write accesses to the CANBIT register are not allowed.
0x1 = Write accesses to the CANBIT register are allowed if the INIT
bit is 1.
5
DAR
R/W
0x0
Disable Automatic Retransmission.
0x0 = Auto-retransmission of disturbed messages is enabled.
0x1 = Auto-retransmission is disabled.
4
RESERVED
R
0x0
3
EIE
R/W
0x0
Error Interrupt Enable
0x0 = No error status interrupt is generated.
0x1 = A change in the BOFF or EWARN bits in the CANSTS register
generates an interrupt.